http://www.sciencedirect.com/science/article/pii/S1674987112001259 |
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| Authors: | Yener Eyuboglu M Santosh Francis O Dudas Enver Akaryah Sun-Lin Chung Kemal Akdag Osman Bektas |
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| Institution: | Department of Geological Engineering.Karadeniz Technical University.61080 Trabzon,Turkey b School of Earth Sciences and Resources.China University of Geosciences(Beijing).29 Xueyuan Road.Beijing 100083.China c Department of Earth,Atmospheric and Planetary Sciences,Massachusetts Institute of Technology.Cambridge.MA 02139.USA d Department of Geological Engineering,Gumushane University,29000 Gumushane.Turkey e Department of Geosciences,National Taiwan University,Taipei 10617.Taiwan |
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| Abstract: | The eastern Pontides orogenic belt provides a window into continental arc magmatism in the Alpine–Himalayan belt. The late Mesozoic–Cenozoic geodynamic evolution of this belt remains controversial. Here we focus on the nature of the transition from the adakitic to non-adakitic magmatism in the Kale area of Gumushane region in NE Turkey where this transition is best preserved. The adakitic lithologies comprise porphyries and hyaloclastites. The porphyries are represented by biotite-rich andesites, hornblende-rich andesite and dacite. The hayaloclastites represent the final stage of adakitic activity and they were generated by eruption/intrusion of adakitic andesitic magma into soft carbonate mud. The non-adakitic lithologies include basaltic-andesitic volcanic and associated pyroclastic rocks. Both rock groups are cutting by basaltic dikes representing the final stage of the Cenozoic magmatism in the study area. We report zircon U-Pb ages of 48.71 ± 0.74 Ma for the adakitic rocks, and 44.68 ± 0.84 Ma for the non-adakitic type, suggesting that there is no significant time gap during the transition from adakitic to non-adakitic magmatism. We evaluate the origin, magma processes and tectonic setting of the magmatism in the southern part of the eastern Pontides orogenic belt. Our results have important bearing on the late Mesozoic–Cenozoic geodynamic evolution of the eastern Mediterranean region. |
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| Keywords: | AdakiteGeochemistryZircon U-Pb geochronologyMagma tectonicsEastern Pontides |
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